Add documentation for libraries

lib/api.dart

@@ -1,3 +1,7 @@
+/// This library provides search functions for searching/scraping Jisho.org.
+/// 
+/// It provides a built-in http client and performs async requests to the server
+/// for different types of requests.
 library unofficial_jisho_api;
 import './src/objects.dart';
 import 'package:http/http.dart' as http;

lib/parser.dart

@@ -1,3 +1,8 @@
+/// This library provides parsing functions for html pages from Jisho.org,
+/// and the associated URI-producing functions.
+/// 
+/// This might be useful for using a CORS proxy, or if you have your own system/library
+/// for providing HTML.
 library unofficial_jisho_parser;
 import './src/objects.dart';